Smart fluid completions, isolations, and safety systems

ABSTRACT

Systems and related methods are disclosed for applying electrorheological fluids in hydro-carbon-producing environments. The systems include a fluid-retaining member having a conductive inner surface and a conductive outer surface. The fluid-retaining member retains a smart fluid. The systems also include a controller that is electrically coupled to a power source and at least one of the conductive inner surface and conductive outer surface of the fluid-retaining member to actuate an electric field or magnetic field across fluid-retaining member. Actuation of the electric field or magnetic field results in a near instantaneous increase in the viscosity of the fluid, causing the fluid to solidify, nearly solidify, gel or otherwise increase in viscosity. The actuated fluid retaining member may be used as a well casing, an isolator, a blowout inhibitor, or in a well insulation system to absorb energy in the event of an explosion.

1. FIELD OF THE INVENTION

The disclosure relates to oil and gas exploration and production, andmore particularly, but not by way of limitation to systems that employvariable-viscosity fluids to generate well completions, isolations, andsafety systems.

2. DESCRIPTION OF RELATED ART

Crude oil and natural gas occur naturally in subterranean deposits andtheir extraction includes drilling a well. The well provides access to aproduction fluid that often contains crude oil and natural gas.Generally, drilling of the well involves deploying a drill string into aformation. The drill string includes a drill bit that removes materialfrom the formation as the drill string is lowered to remove materialfrom the formation and form a wellbore. After drilling and prior toproduction, a casing may be deployed in the wellbore to isolate portionsof the wellbore wall and prevent the ingress of fluids from parts of theformation that are not likely to produce desirable fluids. Aftercompletion, a production string may be deployed into the well tofacilitate the flow of desirable fluids from producing areas of theformation to the surface for collection and processing.

A number of mechanisms may be included in drill strings and productionstrings to protect equipment within the wellbore and ensure consistentoperation such equipment. For example, valves and blow-out preventersmay be installed to prevent rapid, excessive increases in pressure andto prevent backflow. In addition, safety equipment may be installed at awellhead to protect equipment and people in the vicinity of the wellheadin the event of a blowout at the wellhead.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a schematic view of a producing well in which atemporary casing system and isolators are deployed;

FIG. 2A illustrates a schematic view of a subterranean well in which anelectrorheological safety system and a smart fluid blowout inhibitor isdeployed;

FIG. 2B illustrates a schematic view of a subsea well in which theelectrorheological safety system and a smart fluid blowout inhibitor ofFIG. 2A are deployed;

FIG. 3 is a schematic, side cross-section view of a temporary casingthat includes a smart fluid;

FIG. 4 is a schematic, side cross-section view of a blowout inhibitorthat includes a smart fluid;

FIG. 5 is a schematic, side cross-section view of a wellhead insulationsystem that includes a smart fluid; and

FIG. 5A is a schematic, cross-section view of the system of FIG. 5 takenalong the line 5A-5A.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

In the following detailed description of the illustrative embodiments,reference is made to the accompanying drawings that form a part hereof.These embodiments are described in sufficient detail to enable thoseskilled in the art to practice the invention, and it is understood thatother embodiments may be utilized and that logical structural,mechanical, electrical, and chemical changes may be made withoutdeparting from the scope of the invention. To avoid detail not necessaryto enable those skilled in the art to practice the embodiments describedherein, the description may omit certain information known to thoseskilled in the art. The following detailed description is, therefore,not to be taken in a limiting sense, and the scope of the illustrativeembodiments is defined only by the appended claims.

In the drawings and description that follow, like parts are typicallymarked throughout the specification and drawings with the same referencenumerals, respectively. The drawing figures are not necessarily toscale. Certain features of the invention may be shown exaggerated inscale or in somewhat schematic form and some details of conventionalelements may not be shown in the interest of clarity and conciseness.

The embodiments described herein relate to systems, tools, and methodsfor establishing temporary structures in a drilling or productionsystem. In an illustrative embodiment, a temporary wellbore structure,which may be a segment of casing or an isolator, includes afluid-retaining member having an inner surface and an outer surface. Thefluid-retaining member is operable to retain a smart fluid, which may bean electrorheological fluid or a magnetorheological fluid. The temporarystructure includes a controller that is electrically coupled to at leastone of the inner surface and outer surface of the fluid-retainingmember, which form a field generator that is operable to actuate anelectric field or a magnetic field between the inner surface and outersurface of the fluid-retaining member. A surface control subsystem maybe communicatively coupled to the controller and to enable asurface-based well operator to actuate the controller.

A smart fluid is disposed within the fluid-retaining member and operableto solidify, gel, or otherwise increase in viscosity upon actuation ofthe field to increase the rigidity of the fluid-retaining member. Thefluid-retaining member may be a sponge, lattice, hollow cylindricalstructure, or another suitable structure. The fluid-retaining member isprefilled with a smart fluid in an embodiment. In another embodiment,the system includes a fluid delivery system for delivering a smart fluidto the fluid-retaining member.

The fluid-retaining member may be disposed adjacent a wellbore wall, andtherefore operable to form a temporary casing. In another embodiment,the fluid-retaining member may be disposed in an annulus between aproduction string and a wellbore wall or casing, and operable to isolatea well zone that is downhole from the fluid-retaining member from a wellzone that is up-hole from the fluid-retaining member. In anotherembodiment, the fluid-retaining member is disposed within a productionstring or a similar segment of tubing, and operable to act as a blowoutinhibitor in response to the actuation of the field.

Unless otherwise specified, any use of any form of the terms “connect,”“engage,” “couple,” “attach,” or any other term describing aninteraction between elements is not meant to limit the interaction todirect interaction between the elements and may also include indirectinteraction between the elements described. In the following discussionand in the claims, the terms “including” and “comprising” are used in anopen-ended fashion, and thus should be interpreted to mean “including,but not limited to”. Unless otherwise indicated, as used throughout thisdocument, “or” does not require mutual exclusivity.

The various characteristics mentioned above, as well as other featuresand characteristics described in more detail below, will be readilyapparent to those skilled in the art with the aid of this disclosureupon reading the following detailed description of the embodiments, andby referring to the accompanying drawings. Other means may be used aswell.

Referring now to the figures, FIG. 1 shows an example of a productionsystem 100 that includes an isolator 105 and temporary casing segment104, as described in more detail below. The production system 100includes a rig 116 atop the surface 132 of a well 101. Beneath the rig116, the wellbore 108 is formed within the geological formation 106,which is expected to produce hydrocarbons. The wellbore 108 may beformed in the geological formation 106 using a drill string thatincludes a drill bit to remove material from the geological formation106. The wellbore 108 in FIG. 1 is shown as being near-vertical, but maybe formed at any suitable angle to reach a hydrocarbon-rich portion ofthe geological formation 106. As such, in an embodiment, the wellbore108 may follow a vertical, partially vertical, angled, or even apartially horizontal path through the geological formation 106.

Following or during formation of the wellbore 108, a production toolstring 112 may be deployed that includes tools for use in the wellbore108 to operate and maintain the well 101. For example, the productiontool string 112 optionally includes an artificial lift system to assistfluids from the geological formation to reach the surface 132 of thewell 101. Such an artificial lift system may include an electricsubmersible pump 102, sucker rods, a gas lift system, or any othersuitable system for generating a pressure differential. The pump 102receives power from the surface 132 from a power transmission cable 110,which may also be referred to as an “umbilical cable.”

In a production environment, as shown in FIG. 1, production fluids 146are extracted from the formation 106 and delivered to the surface 132via the wellbore 108. As fluid 146 is transported to the surface 132,the fluid passes through the blowout preventer 142 and a fluid diverter144 that diverts fluid 146 to a collection tank 140 for subsequentprocessing and refinement.

In such systems, a well operator may monitor the condition of the well101 and components of the production tool string 112 to ensure that thewell operates efficiently and to determine whether the production fluid146 has desired properties. For example, an operator may want todetermine that the production fluid 146 has a high hydrocarbon contentand a low water content. In some cases, a well operator may determinethat a portion of the formation 106 produces desirable fluids whileanother portion of the foundation produces undesirable fluids, each suchportion of the formation may be referred to as a zone. An operator maysimilarly determine that different zones within a formation producefluid at different rates, or that different zones have higher or lowerhydrostatic pressure relative to one another. For example, the formation106 may have a first zone 156 that interacts with the wellbore 108downhole from a second zone 158. To account for such differingcharacteristics, an operator may include an isolator 105 for separatingthe first zone 156 from the second zone to allow for different rates ofproduction or to allow, for example, production of fluid from the firstzone 156 without allowing production from the second zone 158.Similarly, to prevent the ingress of fluids from a zone in the formation106, the system 100 may include a casing 114 or temporary casing 104that restricts the communication of fluids between the formation 106 andwellbore 108.

In addition, the well operator may take steps to ensure that thepressure in the well does not increase beyond a predetermined threshold,and that pressure within the well or production string 112 does notincrease at a rate that is faster than a predetermined rate. Rapidincreases in pressure, which may be referred to herein as “pressurespikes” may damage equipment in the production string 112 that issubject to the pressure spike or stress other sealing elements that aredesigned to contain the well. To account for such pressure spikes andprevent damage to wellbore equipment, the production system 100 mayinclude a blowout inhibitor 124 that prevents such pressure spikes frombeing transmitted to parts of the production string that are up-holefrom the blowout inhibitor 124.

In an embodiment, a surface controller 120 may be communicativelycoupled to the temporary casing segment 104, isolator 105, or blowoutinhibitor 124 (any of which may be referred to as a “downholecomponent”) by the cable 110 or by a wireless communication protocol,such as mud-pulse telemetry or a similar communications protocol. Thecable 110 may supply power to the downhole component and facilitate thetransmission of data between the surface controller 120 and downholecomponent. In some embodiments, one or more of the downhole componentsmay be permanently or semi-permanently deployed in the wellbore 108, andmay include an on-board controller that functions autonomously or thatcommunicates with the surface controller 120 via a wired or wirelesscommunications protocol.

The production system 100 of FIG. 1 is deployed from the rig 116, whichmay be a drilling rig, a completion rig, a workover rig, or another typeof rig. The rig 116 includes a derrick 109 and a rig floor 111. Theproduction tool string 112 extends downward through the rig floor,through a fluid diverter 144 and up-hole blowout preventer 142 thatprovide a fluidly sealed interface between the wellbore 108 and externalenvironment. The rig 116 may also include a motorized winch 130 andother equipment for extending the tool string 112 into the wellbore 108,retrieving the tool string 112 from the wellbore 108, and positioningthe tool string 112 at a selected depth within the wellbore 108.

While the operating environment shown in FIG. 1 relates to a stationary,land-based rig 116 for raising, lowering and setting the tool string112, in alternative embodiments, mobile rigs, wellbore servicing units(such as coiled tubing units, slickline units, or wireline units), andthe like may be used to lower the tool string 112. Further, while theoperating environment is generally discussed as relating to a land-basedwell, the systems and methods described herein may instead be operatedin subsea well configurations accessed by a fixed or floating platform.Further, while the downhole components are shown as being deployed in aproduction environment, the downhole components may be similarlydeployed in a drilling environment during the formation of the wellbore108.

For example, FIGS. 2A and 2B show a system 200 that includes a drillstring 212 deployed a well. The well is formed by a wellbore 208 thatextends from a surface 232 of the well to or through a subterraneangeological formation 206. The well is illustrated onshore in FIG. 2Awith the system 200 being deployed in land-based well. In anotherembodiment, the system 200 may be deployed in a sub-sea well accessed bya fixed or floating platform 221. In the embodiment illustrated in FIG.2A, the well is formed by a drilling process in which a drill bit 216 isturned by a drill string 212 that extends the drill bit 216 from thesurface 232 to the bottom of the well. The drill string 212 may be madeup of one or more connected tubes or pipes, of varying or similarcross-section. The drill string may refer to the collection of pipes ortubes as a single component, or alternatively to the individual pipes ortubes that comprise the string. The term drill string is not meant to belimiting in nature and may refer to any component or components that arecapable of transferring kinetic, electrical, or hydraulic energy fromthe surface of the well to the drill bit to remove material from thewellbore. In several embodiments, the drill string 212 may include acentral passage disposed longitudinally in the drill string and capableof allowing fluid communication between the surface of the well anddownhole locations.

At or near the surface 232 of the well, the drill string 212 may includeor be coupled to a kelly 228. The kelly 228 may have a square, hexagonalor octagonal cross-section. The kelly 228 is connected at one end to theremainder of the drill string and at an opposite end to a rotary swivel233. The kelly passes through a rotary table 236 that is capable ofrotating the kelly 228 and thus the remainder of the drill string 212and drill bit 216. The rotary swivel 233 allows the kelly 228 to rotatewithout rotational motion being imparted to the rotary swivel 233. Ahook 238, cable 242, traveling block (not shown), and hoist (not shown)are provided to lift or lower the drill bit 216, drill string 20, kelly228 and rotary swivel 233. The kelly 128 and swivel 233 may be raised orlowered as needed to add additional sections of tubing to the drillstring 212 as the drill bit 216 advances, or to remove sections oftubing from the drill string 212 if removal of the drill string 212 anddrill bit 216 from the well is desired.

A reservoir 244 is positioned at the surface 208 and holds drilling mud248 for delivery to the well 202 during drilling operations. A supplyline 252 is fluidly coupled between the reservoir 244 and the innerpassage of the drill string 212. A pump 256 drives fluid through thesupply line 252 and downhole to lubricate the drill bit 216 duringdrilling and to carry cuttings from the drilling process back to thesurface 232. After traveling downhole, the drilling mud 248 returns tothe surface 232 by way of an annulus 260 formed between the drill string212 and the wellbore 208. At the surface 232, the drilling mud 248 isreturned to the reservoir 244 through a return line 264. The drillingmud 248 may be filtered or otherwise processed prior to recirculationthrough the well 202.

A wellhead insulation system 204 may be positioned at or near the top ofthe well to protect equipment and people working in the vicinity in theevent of an explosion or other rapid ejection of matter from the well.The wellhead insulation system 204 may include one or more similarlyformed wellhead insulation system components that absorb energy andprevent the full force of an explosion from being felt outside of thewellhead insulation system 204.

Referring now primarily to FIG. 3, an embodiment of a downhole component300 is shown. The downhole component may be a temporary casing,isolator, or other similar component. The downhole component includes afluid-retaining member, which may be an approximately cylindrical member302 having an outer surface 304 and an inner surface 306. Each of theouter surface 304 and inner surface 306 includes a conductive layer thatis formed from an electrically polarizable material and coupled toeither a ground or an electric potential. For example, in the embodimentof FIG. 3, the outer surface 304 is coupled to a ground 308 and theinner surface is coupled to a potential 310. Each of the ground 308 andpotential 310 may be provided by a control line 312 that is coupled to,for example, a surface controller, as described above with regard toFIG. 1.

The control line 312 is operable to actuate the potential 310, whichgenerates a charge at the inner surface 306 and a corresponding electricfield between the inner surface and the outer surface 304. In analternative embodiment, the potential 310 may be coupled to anelectromagnet that generates a magnetic field between the inner surface306 and the outer surface 304.

The fluid-retaining member may be a hollow structure, a lattice, asponge, or any other suitable structure that is capable of holding afluid, gel, or solidified fluid or gel. The fluid-retaining member maybe prefilled with a smart fluid or filled with a smart fluid upon theoccurrence of an actuation event, which may be the receipt of a controlsignal and corresponding potential from the control line 312 or thereceipt of an actuation signal from another source, such as an onboardcontroller or sensor. To fill the fluid-retaining member upon theoccurrence of an actuation event, a control signal may be generated to avalved reservoir that forces an adequate amount of smart fluid into thefluid-retaining member to fill all or a portion of the fluid-retainingmember upon actuation. The valved reservoir may be analogous to thefluid chamber described below with regard to FIG. 4, and may include apiston that forces fluid from the reservoir into the fluid-retentionmember upon the occurrence of an actuation event.

As referenced herein, a smart fluid is a fluid having a viscosity thatvaries in accordance with a stimulus, such as an electric field ormagnetic field applied across the fluid. Generally, anelectrorheological fluid is a suspension of conductive particles in anelectrically insulating fluid. The apparent viscosity of theelectrorheological fluid may change reversibly in response to theelectric field. For example, a typical electrorheological fluid can gofrom the consistency of liquid water to a gel, a solid state, or anearly solid state, and back, with a response times on the order ofmilliseconds. In an embodiment, the electrorheological fluid comprisesurea-coated particles of barium titanium oxalate suspended in siliconeoil. Similarly, a magnetorheological fluid is a suspension of magneticparticles in a fluid. The apparent viscosity of the magnetorheologicalfluid may also change reversibly in response to a magnetic field. Likean electrorheological fluid, a typical magnetorheological fluid can gofrom the consistency of liquid water to a gel, a solid state, or anearly solid state, and back, with a response time on the order ofmilliseconds. In the illustrative embodiments described below, the smartfluid is generally described as an electrorheological fluid. However,the electrorheological fluid and corresponding actuation mechanisms maybe substituted for a magnetorheological fluid and actuation structurewithout departing from the scope of this disclosure.

In the case of the downhole component 300 shown in FIG. 3 actuation ofthe potential 310 and corresponding electric field may cause an amountof electrorheological fluid stored within the fluid-retaining member togel or solidify, thereby restricting the ability of other fluids to flowthrough the area occupied by the actuated electrorheological fluid. Thismay enable the fluid-retaining structure to function as a temporarycasing or as an isolator to restrict flow between zones in a wellbore orto restrict the ingress of fluid from a wellbore at the site of thetemporary casing.

FIG. 4 shows an alternative embodiment of a downhole component, asdescribed above with regard to FIG. 1, wherein the downhole component isa blowout inhibitor 400. The blowout inhibitor 400 may be deployed as anelement in a production string and may therefore include couplings 432at either end for joining with tubing segments 430 of a productionstring. In an embodiment, the blowout inhibitor 400 includes afluid-retaining member, which may be a hollow tubing segment or similarcylindrical member 402. The cylindrical member may include a fluidchamber 404 that functions as a reservoir to store, for example, anelectrorheological fluid 406. The fluid chamber 404 may be enclosed by avalve 411 that separates the fluid chamber 404 from a conduit thatpasses through the blowout inhibitor 400 and other tubing segments 430in the production string. The fluid chamber 404 may also include apiston 408 that may be actuated to urge the electrorheological fluid 406through the valve 411 and into the conduit. An actuator, such as asolenoid 410, may be included to actuate the piston 408.

The solenoid 410 or another type of actuator may be coupled to acontroller 412 by a first control line 414. A pressure sensor 416 may beincluded at the base of the blowout inhibitor 400 or downhole from theblowout inhibitor 400 to detect pressure spikes. The pressure sensor 416may be coupled to the controller 412 by sensor coupling 418 to generatea signal to the controller 412 that indicates when a pressure spike isdetected. Detection of the pressure spike may result in actuation of afield, such as an electric field or magnetic field, by the controller412.

To generate an electric field, the controller 412 may include or becoupled to a power source, such as a battery or a remote power source.In addition, in an embodiment, the controller 412 is coupled to aconductive inner surface 428 of the cylindrical member 402 or aconductive member 422 having a conductive outer surface 424 to providean actuation signal, or a potential. In an embodiment, either one of theinner surface 428 of the cylindrical member 402 and the outer surface424 of the conductive member 422 is coupled to the controller and theother of the inner surface 428 of the cylindrical member 402 and theouter surface 424 of the conductive member 422 is coupled to a ground. Asecond control line 420 may be provided to couple the conductive member422 to the controller 412 or to couple the conductive member 422 to aground. In another embodiment, on or more of the controller 412 and thesensor 416 may be coupled to one another indirectly via a surfacecontroller.

In an embodiment, the electric field of the blowout inhibitor 400 ofFIG. 4 may be initiated by the receipt of a control signal from asurface controller or upon determination of a pressure spike by thepressure sensor 416, either of which may be referred to as an initiationsignal. In response to an initiation signal, the solenoid 410 mayactuate the piston 408 to cause it to force the electrorheological fluid406 from the fluid chamber 404 to the conduit. The initiation signal mayalso result in the actuation of the electric field so that, as theelectrorheological fluid flows into the conduit, the electrorheologicalfluid may solidify to restrict the ability of the pressure spike topropagate up the production string to affect other components.

In the event that a pressure spike does reach the surface, resulting inan emission of fluid or another type of explosion, similar systems maybe employed to protect people and equipment near the wellhead. Anexample of such a system is shown in FIG. 5. More particularly, FIG. 5shows a wellhead insulation system 500 deployed at a wellhead 504. In anembodiment, the wellhead insulation system 500 includes one or morefluid-retaining members 502, which may be a hollow tubing segment orsimilar cylindrical member, or a segment 522 thereof that is arrangednext to an adjacent segment to form an enclosure around the wellhead504. While the perimeter is shown as being round, the perimeter mayalternatively be square, oval, or any other suitable shape. Eachfluid-retaining member 502 includes a conductive inner plate 506, aconductive outer plate 508, and functions as reservoir to store, forexample, an electrorheological fluid 510.

One of the inner plate 506 and outer plate 508 may be coupled to acontroller 512 by a control line 512 and the other of the inner plate506 and outer plate 508 may be coupled to a ground 520. A pressuresensor 514 may be included in the wellhead 504 to detect a blowout orsimilar event by, for example, detecting pressure spikes. The pressuresensor 514 may be coupled to the controller 512 by sensor coupling 516to generate a signal to the controller 512 that indicates when apressure spike is detected. As described above with regard to theblowout inhibitor of FIG. 4, detection of the pressure spike may resultin actuation of an electric field by the controller 412.

To generate a field, the controller 512 may include or be coupled to apower source, such as a battery or a remote power source. In anembodiment, an electric field of the wellhead insulation system 500 ofFIG. 5 may be initiated by the receipt of a control signal from asurface controller or upon determination of a pressure spike by thepressure sensor 514, either of which may be referred to as an initiationsignal. In an embodiment, the initiation signal results in the actuationof an electric field by causing the controller to apply a potential toone of the inner plate 506 and outer plate 508 so that theelectrorheological fluid solidifies gels. Since significant kineticenergy is absorbed when wellbore material collides with the energizedelectrorheological fluid in the wellhead insulation system 500, thewellhead insulation system 500 will restrict the ability of an explosionto injure nearby equipment or workers.

FIG. 5A shows a top view of the wellhead insulation system 500 of FIG. 5and illustrates that the wellhead insulation system 500 may be formed insegments 522. Each segment may form a portion of the perimeter thatsurrounds the wellhead 504. The inner plate 506 and outer plate 508 maybe coupled to a common controller in parallel or in series, or may eachbe constructed with an onboard controller that is coupled to one or moresensors 514 to detect a blowout or similar event.

In another embodiment, empty segments 522 or an empty fluid-retainingstructure 502 may be constructed to be a hollow, lightweight componentthat can easily be transported to a wellhead 504 and filled onsite withan electrorheological fluid, greatly reducing transportation andassembly costs, and providing for easier installation. In an embodiment,the controller 512 may be omitted and the inner plates 506 or outerplates 508 may be coupled to stable potential to maintain theelectrorheological fluid in an energizes state, thereby negating theneed to detect a blowout in order to protect nearby equipment orpersonnel.

As an alternative to each of the foregoing embodiments, a correspondingembodiment may be implemented that uses a magnetorheological fluid inplace of the electrorheological fluid. In the case of each suchalternative embodiment, the structures disclosed may be nearly identicalwith the exception of the alternative fluid, and the replacement of thestructure used to generate an electric field with a correspondingstructure that generates a magnetic field. For example, a wound coilthat generates an electromagnetic field may be used to apply a magneticfield affect a magnetorheological fluid. In an embodiment in which thefluid retaining structure that houses the magnetorheological fluidcomprises parallel surfaces, each surface may include a shieldedmagnetic plate, or an electromagnet coupled to a magnetizable plate togenerate a magnetic field adjacent the plate. In addition, a permanentmagnet may be deployed into the magnetorheological fluid to actuate thefluid and increase its viscosity to effect a temporary completion, ablowout inhibitor, or a safety system.

In an embodiment in which a magnetorheological fluid is used, anysuitable magnetorheological fluid may be used. The magnetorheologicalfluid may be, for example, a first composition including 20 wt. %carbonyl iron (CI) and fumed silica stabilizer (“Aerosil 200”) insilicone oil (OKS 1050); a second composition including 40 wt. %carbonyl iron (CI) and fumed silica stabilizer (“Aerosil 200”) insilicone oil (OKS 1050); a third composition including 20 wt. % carbonyliron (CI) in silicone oil (OKS 1050); and a fourth composition including40 wt. % carbonyl iron (CI) in silicone oil (OKS 1050); or any othersuitable composition. In each of the representative examples, theviscosity of the magneto-rheological fluid varies as a function ofmagnetic field strength generated by a field generator, such as anelectromagnet or a permanent magnet.

In view of the above disclosure, a number of systems and methodsrelating to the use of electrorheological completions, isolations, andsafety systems are provided. For example, in an illustrative embodiment,a system for use in a wellbore comprises a fluid-retaining member havingan inner surface and an outer surface, the fluid-retaining member beingoperable to retain an electrorheological fluid. The system also includesa controller that is electrically coupled to at least one of the innersurface and outer surface of the fluid-retaining member and operable toactuate an electric field between the inner surface and outer surface ofthe fluid-retaining member. In addition, the system includes a surfacecontrol subsystem communicatively that is coupled to the controller andoperable actuate the controller. The fluid-retaining member may be asponge, a lattice or honeycomb, or a porous foam. In an embodiment, thefluid-retaining member is a hollow cylindrical structure.

The fluid-retaining member may be prefilled with an electrorheologicalfluid, or configured to receive electrorheological fluid from a fluiddelivery system that delivers electrorheological fluid to thefluid-retaining member and forms a portion of the system.Electrorheological fluid disposed within the fluid-retaining member maybe operable to solidify, gel, thicken, or otherwise vary in viscosity inresponse to the actuation of the electric field.

In an embodiment, the fluid-retaining member forms a segment of awellbore casing upon being subjected to the electric field. In anotherembodiment, the fluid-retaining member forms a blowout inhibitor uponbeing subjected to the electric field. The blowout inhibitor may beoperable to obstruct the flow of fluid in the wellbore beyond theblowout inhibitor, effectively stopping upward flow. In an embodiment,the system further includes a pressure sensor coupled to at least one ofthe controller and the surface control. The pressure sensor may beoperable to monitor a pressure within the wellbore downhole from thefluid-retaining member.

At least one of the controller and the surface control may be operableto generate a control signal that results in actuation of the electricfield in response to the pressure sensor determining that the pressurewithin the wellbore downhole from the fluid-retaining member is greaterthan a pre-determined threshold, or in response to determining that thepressure within the wellbore downhole from the fluid-retaining member isincreasing at a rate that exceeds a predetermined threshold rate. In anembodiment, the system includes a fluid delivery subsystem to deliver anelectrorheological fluid to the fluid-retaining member in response tothe control signal.

In accordance with another illustrative embodiment, a method for forminga temporary fluid-restraining member in a wellbore includes providing afluid-retaining member having an inner surface and an outer surfacewithin a wellbore. The fluid-retaining member being operable to retainan electrorheological fluid. The method further includes providing acontroller that is electrically coupled to at least one of the innersurface and outer surface of the fluid-retaining member. In addition themethod includes actuating an electric field between the inner surfaceand outer surface of the fluid-retaining member to energize anelectrorheological fluid.

The fluid-retaining member may include a sponge, lattice, or similarstructure, and may also include a hollow cylindrical structureresembling, for example, a segment of tubing. The method may furtherinclude prefilling the fluid-retaining structure with anelectrorheological fluid or delivering the electrorheological fluid tothe fluid-retaining member in response to receiving a control signal atthe controller. The method may also include causing anelectrorheological fluid disposed within the fluid-retaining member tosolidify in response to the actuation of the electric field.

In an embodiment, the method includes forming a segment of a wellborecasing with the fluid-retaining member in response to the actuation ofthe electric field. In another embodiment, the method includes forming ablow-out preventer with the fluid-retaining member in response to theactuation of the electric field. The method may further comprisecoupling a pressure sensor to the controller and monitoring a pressurewithin the wellbore downhole from the fluid-retaining member. Inaddition, the method may comprise generating a control signal thatresults in actuation of the electric field in response to determiningthat the pressure within the wellbore downhole from the fluid-retainingmember is greater than a pre-determined threshold, or generating acontrol signal that results in actuation of the electric field inresponse to determining that the pressure within the wellbore downholefrom the fluid-retaining member is increasing at a rate that is greaterthan a pre-determined threshold rate. In such an embodiment, the methodmay further include delivering an electrorheological fluid to thefluid-retaining member in response to the control signal.

According to another illustrative embodiment, a wellhead insulationsystem includes at least one fluid-retaining member having an innersurface and an outer surface and a controller that is electricallycoupled to at least one of the inner surface and outer surface of thefluid-retaining member and operable to actuate an electric field betweenthe inner surface and outer surface of the fluid-retaining member. Thewellhead insulation system also includes an electrorheological fluiddisposed within the fluid-retaining member. The electrorheological fluidis operable to solidify, gel, or otherwise increase in viscosity inresponse to the actuation of the electric field. Further, the wellheadinsulation system includes an electrorheological fluid disposed withinthe fluid-retaining member and may include a pressure sensor coupled tothe controller. The he pressure sensor being operable to monitor apressure within a well downhole from the wellhead.

In an embodiment, the fluid-retaining structure is a cylindrical memberthat forms a circumferential barrier around the wellhead. In anotherembodiment, the fluid-retaining structure is a series of structuresarranged in segments to form a barrier around a wellhead. The series ofstructures may be a series of hollow plates having conductive layers oneach side of the hollow plates.

In an embodiment, the controller is operable to generate a controlsignal that results in actuation of the electric field in response todetermining that the pressure within the well is greater than apre-determined threshold. In another embodiment, the controller isoperable to generate a control signal that results in actuation of theelectric field in response to determining that the pressure within thewell is increasing at a rate that is greater than a predeterminedthreshold rate.

In addition to the illustrative embodiments described above, manyexamples of specific combinations are within the scope of thedisclosure, some of which are presented below.

Example One

A system for use in a wellbore, the system having a fluid-retainingmember having an inner surface and an outer surface, the fluid-retainingmember being operable to retain a smart fluid. The system also includesa controller, which is electrically coupled to at least one of the innersurface and outer surface of the fluid-retaining member and operable toactuate a field between the inner surface and outer surface of thefluid-retaining member. The system also includes a surface controlsubsystem communicatively coupled to the controller and operable actuatethe controller.

Example Two

A system for use in a wellbore, the system having a fluid-retainingmember having an inner surface and an outer surface, the fluid-retainingmember being operable to retain an electrorheological fluid. The systemalso includes a controller, which is electrically coupled to at leastone of the inner surface and outer surface of the fluid-retaining memberand operable to actuate an electric field between the inner surface andouter surface of the fluid-retaining member. The system also includes asurface control subsystem communicatively coupled to the controller andoperable actuate the controller.

Example Three

A system for use in a wellbore, the system having a fluid-retainingmember having an inner surface and an outer surface, the fluid-retainingmember being operable to retain an electrorheological fluid. The systemalso includes a controller, which is magnetically coupled to at leastone of the inner surface and outer surface of the fluid-retaining memberand operable to actuate an electric field between the inner surface andouter surface of the fluid-retaining member. The system also includes asurface control subsystem communicatively coupled to the controller andoperable actuate the controller.

Example Four

A system for use in a wellbore, the system having a fluid-retainingmember having an inner surface and an outer surface, the fluid-retainingmember being operable to retain a smart fluid. The system also includesa controller, which is electrically coupled to at least one of the innersurface and outer surface of the fluid-retaining member and operable toactuate a field between the inner surface and outer surface of thefluid-retaining member. The system also includes a surface controlsubsystem communicatively coupled to the controller and operable actuatethe controller. The fluid-retaining member is selected from the groupconsisting of a sponge, a lattice, and a hollow cylindrical structure.

Example Five

A system for use in a wellbore, the system having a fluid-retainingmember having an inner surface and an outer surface, the fluid-retainingmember being prefilled with and operable to retain a smart fluid. Thesystem also includes a controller, which is electrically coupled to atleast one of the inner surface and outer surface of the fluid-retainingmember and operable to actuate a field between the inner surface andouter surface of the fluid-retaining member. The system also includes asurface control subsystem communicatively coupled to the controller andoperable actuate the controller.

Example Six

A system for use in a wellbore, the system having a fluid-retainingmember having an inner surface and an outer surface, the fluid-retainingmember being prefilled with and operable to retain a smart fluid. Thesystem also includes a controller, which is electrically coupled to atleast one of the inner surface and outer surface of the fluid-retainingmember and operable to actuate a field between the inner surface andouter surface of the fluid-retaining member. The system includes asurface control subsystem communicatively coupled to the controller andoperable actuate the controller and also includes a fluid deliverysystem for the smart fluid to the fluid-retaining member.

Example Seven

A system for use in a wellbore, the system having a fluid-retainingmember having an inner surface and an outer surface, the fluid-retainingmember being operable to retain a smart fluid. The system also includesa controller, which is electrically coupled to at least one of the innersurface and outer surface of the fluid-retaining member and operable toactuate a field between the inner surface and outer surface of thefluid-retaining member. The system also includes a surface controlsubsystem communicatively coupled to the controller and operable actuatethe controller. The smart fluid is disposed within the fluid-retainingmember yet is operable to solidify in response to the actuation of thefield.

Example Eight

A system for use in a wellbore, the system having a fluid-retainingmember having an inner surface and an outer surface, the fluid-retainingmember being operable to retain a smart fluid. The system also includesa controller, which is electrically coupled to at least one of the innersurface and outer surface of the fluid-retaining member and operable toactuate a field between the inner surface and outer surface of thefluid-retaining member. The system also includes a surface controlsubsystem communicatively coupled to the controller and operable actuatethe controller. The smart fluid is disposed within the fluid-retainingmember yet is operable to solidify in response to the actuation of thefield. The fluid-retaining member may be a segment of a wellbore casingto be formed in response to the actuation of the field or a blowoutinhibitor in response to the actuation of the field.

Example Nine

A system for use in a wellbore, the system having a fluid-retainingmember having an inner surface and an outer surface, the fluid-retainingmember being operable to retain a smart fluid. The system also includesa controller, which is electrically coupled to at least one of the innersurface and outer surface of the fluid-retaining member and operable toactuate a field between the inner surface and outer surface of thefluid-retaining member. The system also includes a surface controlsubsystem communicatively coupled to the controller and operable actuatethe controller. In addition, the system includes a pressure sensorcoupled to at least one of the controller and the surface control, thepressure sensor being operable to monitor a pressure within the wellboredownhole from the fluid-retaining member.

Example Ten

A system for use in a wellbore, the system having a fluid-retainingmember having an inner surface and an outer surface, the fluid-retainingmember being operable to retain a smart fluid. The system also includesa controller, which is electrically coupled to at least one of the innersurface and outer surface of the fluid-retaining member and operable toactuate a field between the inner surface and outer surface of thefluid-retaining member. The system also includes a surface controlsubsystem communicatively coupled to the controller and operable actuatethe controller. In addition, the system includes a pressure sensorcoupled to at least one of the controller and the surface control, thepressure sensor being operable to monitor a pressure within the wellboredownhole from the fluid-retaining member. In accordance with the system,at least one of the controller and the surface control is operable togenerate a control signal that results in actuation of the field inresponse to the pressure sensor determining that the pressure within thewellbore downhole from the fluid-retaining member is greater than apre-determined threshold. The system may also include a fluid deliverysubsystem to deliver a smart fluid to the fluid-retaining member inresponse to the control signal.

Example Eleven

A system for use in a wellbore, the system having a fluid-retainingmember having an inner surface and an outer surface, the fluid-retainingmember being operable to retain a smart fluid. The system also includesa controller, which is electrically coupled to at least one of the innersurface and outer surface of the fluid-retaining member and operable toactuate a field between the inner surface and outer surface of thefluid-retaining member. The system also includes a surface controlsubsystem communicatively coupled to the controller and operable actuatethe controller. In addition, the system includes a pressure sensorcoupled to at least one of the controller and the surface control, thepressure sensor being operable to monitor a pressure within the wellboredownhole from the fluid-retaining member. In accordance with the system,at least one of the controller and the surface control is operable togenerate a control signal that results in actuation of the field inresponse to the pressure sensor determining that the pressure within thewellbore downhole from the fluid-retaining member is increasing at arate that is greater than a pre-determined threshold rate. The systemmay also include a fluid delivery subsystem to deliver a smart fluid tothe fluid-retaining member in response to the control signal.

Example Twelve

A method for forming a temporary fluid-restraining member in a wellboreincludes providing a fluid-retaining member having an inner surface andan outer surface. The fluid-retaining member is operable to retain asmart fluid. The method further includes providing a controller that iselectrically coupled to at least one of the inner surface and outersurface of the fluid-retaining member, and actuating a field between theinner surface and outer surface of the fluid-retaining member.

Example Thirteen

A method for forming a temporary fluid-restraining member in a wellboreincludes providing a fluid-retaining member having an inner surface andan outer surface. The fluid-retaining member is operable to retain asmart fluid. The method further includes providing a controller that iselectrically coupled to at least one of the inner surface and outersurface of the fluid-retaining member, and actuating a field between theinner surface and outer surface of the fluid-retaining member. In thisexample, the smart fluid is a magnetorheological fluid and the field isa magnetic field.

Example Fourteen

A method for forming a temporary fluid-restraining member in a wellboreincludes providing a fluid-retaining member having an inner surface andan outer surface. The fluid-retaining member is operable to retain asmart fluid. The method further includes providing a controller that iselectrically coupled to at least one of the inner surface and outersurface of the fluid-retaining member, and actuating a field between theinner surface and outer surface of the fluid-retaining member. In thisexample, the smart fluid is an electrorheological fluid and the field isan electric field.

Example Fifteen

A method for forming a temporary fluid-restraining member in a wellboreincludes providing a fluid-retaining member having an inner surface andan outer surface. The fluid-retaining member is operable to retain asmart fluid. The method further includes providing a controller that iselectrically coupled to at least one of the inner surface and outersurface of the fluid-retaining member, and actuating a field between theinner surface and outer surface of the fluid-retaining member. Thefluid-retaining member is selected from the group consisting of asponge, a lattice, and a hollow cylindrical structure.

Example Sixteen

A method for forming a temporary fluid-restraining member in a wellboreincludes providing a fluid-retaining member having an inner surface andan outer surface. The fluid-retaining member is operable to retain asmart fluid. The method further includes providing a controller that iselectrically coupled to at least one of the inner surface and outersurface of the fluid-retaining member, and actuating a field between theinner surface and outer surface of the fluid-retaining member. Themethod further includes prefilling the fluid-retaining structure with asmart fluid.

Example Seventeen

A method for forming a temporary fluid-restraining member in a wellboreincludes providing a fluid-retaining member having an inner surface andan outer surface. The fluid-retaining member is operable to retain asmart fluid. The method further includes providing a controller that iselectrically coupled to at least one of the inner surface and outersurface of the fluid-retaining member, and actuating a field between theinner surface and outer surface of the fluid-retaining member. Themethod further includes delivering a smart fluid to the fluid-retainingmember in response to receiving a control signal at the controller.

Example Eighteen

A method for forming a temporary fluid-restraining member in a wellboreincludes providing a fluid-retaining member having an inner surface andan outer surface. The fluid-retaining member is operable to retain asmart fluid. The method further includes providing a controller that iselectrically coupled to at least one of the inner surface and outersurface of the fluid-retaining member, and actuating a field between theinner surface and outer surface of the fluid-retaining member. Themethod further includes causing a smart fluid disposed within thefluid-retaining member to solidify in response to the actuation of thefield.

Example Nineteen

A method for forming a temporary fluid-restraining member in a wellboreincludes providing a fluid-retaining member having an inner surface andan outer surface. The fluid-retaining member is operable to retain asmart fluid. The method further includes providing a controller that iselectrically coupled to at least one of the inner surface and outersurface of the fluid-retaining member, and actuating a field between theinner surface and outer surface of the fluid-retaining member. Themethod further includes forming a segment of a wellbore casing with thefluid-retaining member in response to the actuation of the field.

Example Twenty

A method for forming a temporary fluid-restraining member in a wellboreincludes providing a fluid-retaining member having an inner surface andan outer surface. The fluid-retaining member is operable to retain asmart fluid. The method further includes providing a controller that iselectrically coupled to at least one of the inner surface and outersurface of the fluid-retaining member, and actuating a field between theinner surface and outer surface of the fluid-retaining member. Themethod further includes forming a blow-out preventer with thefluid-retaining member in response to the actuation of the field.

Example Twenty-One

A method for forming a temporary fluid-restraining member in a wellboreincludes providing a fluid-retaining member having an inner surface andan outer surface. The fluid-retaining member is operable to retain asmart fluid. The method further includes providing a controller that iselectrically coupled to at least one of the inner surface and outersurface of the fluid-retaining member, and actuating a field between theinner surface and outer surface of the fluid-retaining member. Themethod further includes forming a blow-out preventer with thefluid-retaining member in response to the actuation of the field. Inaddition, the method includes coupling a pressure sensor to thecontroller and monitoring a pressure within the wellbore downhole fromthe fluid-retaining member.

Example Twenty-Two

A method for forming a temporary fluid-restraining member in a wellboreincludes providing a fluid-retaining member having an inner surface andan outer surface. The fluid-retaining member is operable to retain asmart fluid. The method further includes providing a controller that iselectrically coupled to at least one of the inner surface and outersurface of the fluid-retaining member, and actuating a field between theinner surface and outer surface of the fluid-retaining member. Themethod further includes forming a blow-out preventer with thefluid-retaining member in response to the actuation of the field. Inaddition, the method includes generating a control signal that resultsin actuation of the field in response to determining that the pressurewithin the wellbore downhole from the fluid-retaining member is greaterthan a pre-determined threshold.

Example Twenty-Three

A method for forming a temporary fluid-restraining member in a wellboreincludes providing a fluid-retaining member having an inner surface andan outer surface. The fluid-retaining member is operable to retain asmart fluid. The method further includes providing a controller that iselectrically coupled to at least one of the inner surface and outersurface of the fluid-retaining member, and actuating a field between theinner surface and outer surface of the fluid-retaining member. Themethod further includes forming a blow-out preventer with thefluid-retaining member in response to the actuation of the field. Inaddition, the method includes generating a control signal that resultsin actuation of the field in response to determining that the pressurewithin the wellbore downhole from the fluid-retaining member isincreasing at a rate that is greater than a pre-determined thresholdrate.

Example Twenty-Four

A method for forming a temporary fluid-restraining member in a wellboreincludes providing a fluid-retaining member having an inner surface andan outer surface. The fluid-retaining member is operable to retain asmart fluid. The method further includes providing a controller that iselectrically coupled to at least one of the inner surface and outersurface of the fluid-retaining member, and actuating a field between theinner surface and outer surface of the fluid-retaining member. Themethod further includes forming a blow-out preventer with thefluid-retaining member in response to the actuation of the field. Inaddition, the method includes generating a control signal that resultsin actuation of the field in response to determining that the pressurewithin the wellbore downhole from the fluid-retaining member isincreasing at a rate that is greater than a pre-determined thresholdrate, or in response to determining that the pressure is greater than apre-determined threshold. The method also includes delivering a smartfluid to the fluid-retaining member in response to the control signal.

Example Twenty-Five

A wellhead insulation system having at least one fluid-retaining memberthat includes an inner surface and an outer surface. The system has apower source operable to actuate a field between the inner surface andouter surface of the fluid-retaining member, and a smart fluid isdisposed within the fluid-retaining member. The smart fluid is operableto solidify in response to the field.

Example Twenty-Six

A wellhead insulation system having at least one fluid-retaining memberthat includes an inner surface and an outer surface. The system has apower source operable to actuate a field between the inner surface andouter surface of the fluid-retaining member, and a smart fluid isdisposed within the fluid-retaining member. The smart fluid is operableto solidify in response to the field. The smart fluid is amagnetorheological fluid and the field is a magnetic field.

Example Twenty-Six

A wellhead insulation system having at least one fluid-retaining memberthat includes an inner surface and an outer surface. The system has apower source operable to actuate a field between the inner surface andouter surface of the fluid-retaining member, and a smart fluid isdisposed within the fluid-retaining member. The smart fluid is operableto solidify in response to the field. The smart fluid is anelectrorheological fluid and the field is an electric field.

Example Twenty-Seven

A wellhead insulation system having at least one fluid-retaining memberthat includes an inner surface and an outer surface. The system has apower source operable to actuate a field between the inner surface andouter surface of the fluid-retaining member, and a smart fluid isdisposed within the fluid-retaining member. The smart fluid is operableto solidify in response to the field. The at least one fluid-retainingmember includes a cylindrical member that forms a circumferentialbarrier around the wellhead.

Example Twenty-Eight

A wellhead insulation system having at least one fluid-retaining memberthat includes an inner surface and an outer surface. The system has apower source operable to actuate a field between the inner surface andouter surface of the fluid-retaining member, and a smart fluid isdisposed within the fluid-retaining member. The smart fluid is operableto solidify in response to the field. The at least one fluid-retainingmember includes a series of structures arranged in segments to form abarrier around a wellhead.

Example Twenty-Eight

A wellhead insulation system having at least one fluid-retaining memberthat includes an inner surface and an outer surface. The system has apower source operable to actuate a field between the inner surface andouter surface of the fluid-retaining member, and a smart fluid isdisposed within the fluid-retaining member. The smart fluid is operableto solidify in response to the field. The at least one fluid-retainingmember includes a series of structures arranged in segments to form abarrier around a wellhead, and the series of structures includes aseries of hollow plates having conductive layers on each side of thehollow plates.

Example Twenty-Nine

A wellhead insulation system having at least one fluid-retaining memberthat includes an inner surface and an outer surface. The system has apower source operable to actuate a field between the inner surface andouter surface of the fluid-retaining member, and a smart fluid isdisposed within the fluid-retaining member. The smart fluid is operableto solidify in response to the field. The fluid-retaining memberincludes a sponge or a lattice.

Example Thirty

A wellhead insulation system having at least one fluid-retaining memberthat includes an inner surface and an outer surface. The system has apower source operable to actuate a field between the inner surface andouter surface of the fluid-retaining member, and a smart fluid isdisposed within the fluid-retaining member. The smart fluid is operableto solidify in response to the field. The system further includes acontroller that is electrically coupled to the power source and at leastone of the inner surface and outer surface of the fluid-retaining memberand operable to actuate an electric or a magnetic field between theinner surface and outer surface of the fluid-retaining member. Inaddition, the system includes a pressure sensor coupled to thecontroller. The pressure sensor is operable to monitor a pressure withina well downhole from the wellhead.

Example Thirty-One

A wellhead insulation system having at least one fluid-retaining memberthat includes an inner surface and an outer surface. The system has apower source operable to actuate a field between the inner surface andouter surface of the fluid-retaining member, and a smart fluid isdisposed within the fluid-retaining member. The smart fluid is operableto solidify in response to the field. The system further includes acontroller that is electrically coupled to the power source and at leastone of the inner surface and outer surface of the fluid-retaining memberand operable to actuate an electric or a magnetic field between theinner surface and outer surface of the fluid-retaining member. Inaddition, the system includes a pressure sensor coupled to thecontroller. The pressure sensor is operable to monitor a pressure withina well downhole from the wellhead. The controller is operable togenerate a control signal that results in actuation of the electricfield or magnetic field in response to determining that the pressurewithin the well is greater than a pre-determined threshold.

Example Thirty-Two

A wellhead insulation system having at least one fluid-retaining memberthat includes an inner surface and an outer surface. The system has apower source operable to actuate a field between the inner surface andouter surface of the fluid-retaining member, and a smart fluid isdisposed within the fluid-retaining member. The smart fluid is operableto solidify in response to the field. The system further includes acontroller that is electrically coupled to the power source and at leastone of the inner surface and outer surface of the fluid-retaining memberand operable to actuate an electric or a magnetic field between theinner surface and outer surface of the fluid-retaining member. Inaddition, the system includes a pressure sensor coupled to thecontroller. The pressure sensor is operable to monitor a pressure withina well downhole from the wellhead. The controller is operable togenerate a control signal that results in actuation of the electricfield or magnetic field in response to determining that the pressurewithin the well is greater than a pre-determined threshold rate.

It will be understood that the above description of preferredembodiments is given by way of example only and that variousmodifications may be made by those skilled in the art. The abovespecification, examples, and data provide a complete description of thestructure and use of exemplary embodiments of the invention. Althoughvarious embodiments of the invention have been described above with acertain degree of particularity, or with reference to one or moreindividual embodiments, those skilled in the art could make numerousalterations to the disclosed embodiments without departing from thescope of the claims.

We claim:
 1. A system for use in a wellbore, the system comprising: afluid-retaining member having an inner surface and an outer surface, thefluid-retaining member being operable to retain a smart fluid; acontroller, the controller being electrically coupled to at least one ofthe inner surface and outer surface of the fluid-retaining member andoperable to actuate a field between the inner surface and outer surfaceof the fluid-retaining member; a surface control subsystemcommunicatively coupled to the controller and operable actuate thecontroller.
 2. The system of claim 1, wherein the field is an electricfield.
 3. The system of claim 1, wherein the field is a magnetic field.4. The system of claim 1, wherein the fluid-retaining member is selectedfrom the group consisting of a sponge, a lattice, and a hollowcylindrical structure.
 5. The system of claim 1, wherein thefluid-retaining member is prefilled with the smart fluid.
 6. The systemof claim 1, further comprising a fluid delivery system for the smartfluid to the fluid-retaining member.
 7. The system of claim 1, furthercomprising: a smart fluid disposed within the fluid-retaining member,the smart fluid being operable to solidify in response to the actuationof the field; and a pressure sensor coupled to at least one of thecontroller and the surface control, the pressure sensor being operableto monitor a pressure within the wellbore downhole from thefluid-retaining member, wherein the fluid-retaining member forms ablowout inhibitor in response to the actuation of the field.
 8. A methodfor forming a temporary fluid-restraining member in a wellbore, themethod comprising: providing a fluid-retaining member having an innersurface and an outer surface within a wellbore, the fluid-retainingmember being operable to retain a smart fluid; providing a controller,the controller being electrically coupled to at least one of the innersurface and outer surface of the fluid-retaining member; and actuating afield between the inner surface and outer surface of the fluid-retainingmember.
 9. The method of claim 7, wherein the smart fluid comprises amagnetorheological fluid and the field comprises a magnetic field. 10.The method of claim 7, wherein the smart fluid comprises anelectrorheological fluid and the field comprises an electric field. 11.The method of claim 7, wherein the fluid-retaining member is selectedfrom the group consisting of a sponge, a lattice, and a hollowcylindrical structure.
 12. The method of claim 7, further comprisingprefilling the fluid-retaining structure with a smart fluid.
 13. Themethod of claim 7, further comprising delivering a smart fluid to thefluid-retaining member in response to receiving a control signal at thecontroller.
 14. The method of claim 7, further comprising causing asmart fluid disposed within the fluid-retaining member to solidify inresponse to the actuation of the field.
 15. A wellhead insulation systemcomprising: at least one fluid-retaining member having an inner surfaceand an outer surface; a power source operable to actuate a field betweenthe inner surface and outer surface of the fluid-retaining member; and asmart fluid disposed within the fluid-retaining member, the smart fluidbeing operable to solidify in response to the field.
 16. The system ofclaim 15, wherein the smart fluid comprises a magnetorheological fluidand wherein the field comprises a magnetic field.
 17. The system ofclaim 15, wherein the smart fluid comprises an electrorheological fluidand wherein the field comprises an electric field.
 18. The system ofclaim 15, wherein the at least one fluid-retaining member comprises acylindrical member that forms a circumferential barrier around thewellhead.
 19. The system of claim 15, wherein the at least onefluid-retaining member comprises a series of structures arranged insegments to form a barrier around a wellhead.
 20. The system of claim15, further comprising: a controller, the controller being electricallycoupled to the power source and at least one of the inner surface andouter surface of the fluid-retaining member and operable to actuate anelectric field between the inner surface and outer surface of thefluid-retaining member; and a pressure sensor coupled to the controller,the pressure sensor being operable to monitor a pressure within a welldownhole from the wellhead, wherein the controller is operable togenerate a control signal that results in actuation of the electricfield in response to determining that the pressure within the well isgreater than a pre-determined threshold rate.